In a 2-3 page paper, using APA-style formatting, define and
discuss the concept of ecological services. Then, review the “Ecological
Services of Rivers” outlined in Mini Lecture: Water Resources and Water
Pollution. From the list, identify two services you believe are the
most important and cite at least 3 reasons why. Also, choose two
services that you think are most likely to decline due to human
influence and cite at least 3 examples of the result of decline of those
services.
Below is the mini lecture:
Life on planet Earth
would be impossible without water. All life forms, from unicellular
bacteria to multicellular plants and animals, contain water. Humans are
composed of approximately 60 percent water by body weight and we depend
on water, not only for our survival, but for our convenience: We drink
it, cook with it, wash in it, travel on it, and use an enormous amount
of it for agriculture, manufacturing, mining, energy, production, and
waste disposal. Though 71% of the Earth’s surface is covered in water,
only 0.024% of the overall water supply is available as liquid
freshwater that is easily accessible. It is one of the most poorly
managed resources, easily wasted and often polluted. The available
freshwater is collected, purified and distributed in the hydrologic
cycle, but this cycle is easily interrupted by overloading with
pollution, reducing wetlands, and reducing forests.
We get water from
groundwater and surface water. Groundwater is water that seeps into the
ground between spaces in soil and gravel until it reaches impenetrable
bedrock. One of the most important sources of freshwater. The top of the
groundwater zone that moves up and down based on weather is the water
table. The water table drops in level when humans remove water at a
faster rate than it is replenished. Surface water is freshwater from
precipitation and melted snow that flows into lakes, wetlands, rivers,
and eventually into the oceans.
Water shortages are caused by many
factors including dry climate and drought. In some places, the human
population uses water at a faster rate than the water is replenished.
30% of the Earth’s land mass now experiences severe or extreme drought
and 1 billion people lacked regular access to clean water for drinking,
cooking, and washing.
Water Supplies
Aquifers, underground water
supplies, are renewable as long as the groundwater doesn’t become
contaminated and withdrawn too quickly. Most aquifers around the world,
and in the largest food producing countries, are being used up quicker
than their rate of replenishment. Dam and reservoir systems are used to
capture and hold runoff water. The collected water can be released at
need to control flooding, supply water for farming and cities, and to
produce electricity. The use of dams and reservoirs has increased the
amount of reliable surface runoff by one-third. Unfortunately, these
systems also displace people, flood productive lands, and disrupt the
ecological services rivers provide.
Tunnels, aqueducts, and
underground pipes transfer runoff from dams and reservoirs to water-poor
areas. These transfer systems can be wasteful and environmentally
harmful by shrinking the water source as more is transferred to
water-poor areas. Another option for freshwater is desalinization which
involves removing salts from ocean or brackish water. Usually
desalinization costs a lot because of the energy required; it also kills
many marine organisms and creates salty wastewater, which is usually
dumped in the ocean, increasing the salinity of the local ocean.
Sustainable Water Use
Cutting
water waste is quicker and easier than trying to provide new freshwater
supplies. Most water used is lost through evaporation, leaks, and other
losses. One main reason for water wastage is the low cost to users with
water costs usually being subsidized by governments. One way to
sustainably use water is to cut water waste in irrigation. Most
agriculture practices use flood irrigation that deliver more water than
needed to the plants and loses up to 40% of water through runoff and
evaporation. Drip irrigation and low-energy, precision sprinklers
deliver less water, but target the plants better to insure that the
water reaches the plants.
Other sustainable water use solutions are
using water saving appliances in the home, especially the kitchen and
bathroom. Using grey water (recycled water from the house, like shower
water) to water lawns and gardens. Lining canals so that water is not
lost on the way to irrigation ditches and only adding water when the
soil requires it.
Ecological Services
Our water resources provide
important ecological and economic services. These are particularly
evident in the services provided by rivers. According to the Ecological
Society of America, ecosystem (or ecological) services are processes by
which the environment produces resources that we often take for granted.
Although ecological systems support plants and animals, they also
provide vital services to people that improve well-being. Ecosystems
purify water and air, reduce flood and drought risks, provide food and
fuel, and support recreation, to name a few of their many benefits. To
ensure these valuable services continue, our natural areas must be
healthy.
Natural ecosystems and the plants and animals within them
provide humans with services that would be very difficult to duplicate.
While it is often impossible to place an accurate monetary amount on
ecosystem services, we can calculate some of the financial values.
According to the Ecological Society of America, many of these services
are preformed seemingly for “free,” yet are worth many trillions of
dollars, for example:
Much of the Mississippi River Valley’s natural
flood protection services were destroyed when adjacent wetlands were
drained and channels altered. As a result, the 1993 floods resulted in
property damages estimated at twelve billion dollars partially from the
inability of the Valley to lessen the impacts of the high volumes of
water.
Eighty percent of the world’s population relies upon natural
medicinal products. Of the top 150 prescription drugs used in the U.S.,
118 originate from natural sources: 74 percent from plants, 18 percent
from fungi, 5 percent from bacteria, and 3 percent from one vertebrate
(snake species). Nine of the top 10 drugs originate from natural plant
products.
Over 100,000 different animal species — including bats,
bees, flies, moths, beetles, birds, and butterflies — provide free
pollination services. One third of human food comes from plants
pollinated by wild pollinators. The value of pollination services from
wild pollinators in the U.S. alone is estimated at four to six billion
dollars per year.
In addition to the “services” listed above, our ecosystems provide the following critical services to us:
protect people from the sun’s harmful ultraviolet rays
cycle and move nutrients
detoxify and decompose wastes
control agricultural pests
maintain biodiversity
generate and preserve soils and renew their fertility
contribute to climate stability
regulate disease carrying organisms
pollinate crops and natural vegetation
Water Pollution
Water
pollution is a global problem that varies in magnitude and type of
pollutant from one region to another. Water pollutants come from both
natural sources and human activities. Natural sources of pollution tend
to be local concerns, but human-generated pollution is generally more
widespread. Sources of water pollution are classified into two types,
point source pollution and nonpoint source pollution. Point source
pollution describes discharge pollutions into bodies of surface water at
specific locations, such as drain pipes or ditches. Pollutants that
enter bodies of water over large areas rather than at single point cause
nonpoint source pollution, also called polluted runoff.
Agricultural
practices, industrial facilities, and mining are the three main causes
of water pollution and pollute the water with sediment and harmful
chemicals. Water pollution can have harmful effects, often spreading
infectious diseases. Fast moving streams and rivers have the ability to
clean themselves of pollution through dilution and the breakdown of
wastes with bacteria. This natural cleaning can stop if the rivers are
over polluted. Lakes and reservoirs cannot clean themselves in the same
manner and are more easily affected by pollution. These standing bodies
of water can be susceptible to eutrophication, which is the nutrient
enrichment of shallow bodies of water causing “blooms” of microorganisms
reducing lake productivity and killing other organisms.
Pollutants,
such as fertilizers, pesticides, and gasoline, can affect ground water
and harm freshwater drinking supplies for many people. Preventing
pollution of groundwater is the only effective way to keep groundwater
safe since the standing water cannot easily cleanse itself of
pollutants. In most developed countries, groundwater is purified and
treated to meet government safe standards, but these purifying
techniques aren’t available in all countries.
Besides freshwater,
oceans are also becoming polluted. With 40% of the world’s population
living near the coast, wetlands, estuaries, and coral reefs suffer from
the most pollution. Most marine pollution, >80%, occurs from land
pollution via agricultural and sewage runoff. Oil is also polluting the
ocean. Most of these pollutants reach the ocean through tanker accidents
and oil that escapes from offshore drilling rigs. Volatile organic
hydrocarbons in the oil can kill many organisms on contact or tarlike
balls of oil can cover seabirds and marine mammals, hindering their
ability to fly or swim.
Dealing with Water Pollution
There are
laws in place to help reduce water pollution by setting standards on how
much chemical can be discharged into the water at a point source.
Sewage treatment is also another way to reduce pollution. Primary sewage
treatment is a physical process that uses screens and grit tanks to
remove large floating objects and allows sediment to settle out of water
column.
Secondary sewage treatment is a biological process in which
aerobic bacteria remove as much as 90% of dissolved and biodegradable
organic wastes. Conventional sewage treatment can be redesigned to
remove toxic and hazardous chemicals, preventing them from being
discharged into sludge or water. Also, homes and business could install
composting toilet systems to reduce the amount of waste being treated at
plants. The current shift in water pollution is away from removing
pollution after the fact to stopping pollution from entering water in
the beginning.
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